Piston ring



Patented July 31, 1951 UHTE STATES ATENT OFFICE PISTON RING ApplicationDecember 26, 1947, Serial No. 793,791

19 Claims.

The invention relates generally to piston rings and more particularly toa piston ring of sheet metal construction.

The general object of the invention is to provide a novel sheet metalpiston ring construction for use in an internal combustion engine or thelike and adapted to provide eii'ective oil control in the cylinder.

Another object is to provide a novel sheet metal piston ring having acylinder contacting edge or flange for scraping oil from the cylinderwall, with the ring vented inwardly on both sides of such flange so thatoil removed by the flange is free to flow inwardly and be returned tothe crankcase of the engine through the piston.

A further and more specific object is to provide a piston ring of sheetmetal construction comprising three axiallyspaced rails or flanges ofsegmental construction for circumferential extensibility, with thesegments of each outer rail flexibly connected to the segments of theother outer rail and to the segments of the intermediate rail.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings, inwhich:

Figure 1 is a transverse sectional view of a piston and a portion of thecylinder in which the piston operates, the piston having a piston ringembodying the features of the invention.

Fig. 2 is an enlarged fragmentary plan view of the piston ring shown inFig. 1. Fig. 3 is a fragmentary view of the outer periphery of the ring.

to provide a cylinder-engaging flange or rail intermediate the sides ofthe ring, with thering so constructed that oil collecting on either sideof the rail may flow inwardly through the ring for return through thering-receiving groove and piston to the crankcase. The ring may have,and preferably does have, in addition to the intermediate rail,- a pairof outer cylinder-engaging rails located at the sides of the ring, sothat the ring presents three cylinder-contacting edges for removingexcess oil from the wall surface of the cylinder during reciprocation ofthe piston. All of the rails are here shown as being of segmentalconstruction, with the segments of the respective rails interconnectedin such a manner as to provide for circumferential expansion ofthe'ring. Generally described. the ring may be said to be E-shaped inradial cross section with each of the three horizontal bars of the Ecomprising a single layer of metal. The web members arecircumferentially spaced from one another and are so formed as toprovide relatively large openings at'the inner periphery of the ring sothat oil collected on either side of the intermediate or center rail mayflow freely through the ring inwardly to th ring-receiving groove in thepiston. The ring may be formed from a strip of sheet metal having alength substantially equal to the circumference of the ring, the stripbeing punched and sheared as illustrated in Fig. 7 and then benttoprovide the ultimate form.

In Fig. 1 there is shown a fragmentary portion of a cylinder Ill with apiston ll mounted therein. Formed inthe Periphery of the piston ll is aring groove l2 in which a ring, indicated generally at l3,-is mounted,the ring l3 being more fully illustrated in the higher-numbered figures.

. The ring I3 in the embodiment shown in the drawings comprises threeaxially spaced rails, the two outer rails being indicated generally at il and the intermediate rail being indicated generally at [5. All threerails are preferably of segmental construction. Thus, each of the outerrails comprises a plurality of segments l6 while the intermediate raill5 comprises a plurality of segments H. The segments in the respectiverails are oircumferentially aligned so that each rail comprises a singlethickness or layer of metal.

' The segments of the respective rails constitute only a portion of theradial width of the ring and are connected by a web structure formed topermit the ring to expand circumferentially. In the form shown in thedrawings, each of the segments ll forming the intermediate rail isconnected to one of the segments-in one of the outer rails, ad-

joining segments I! being connected to segments in opposite outer railsto provide a staggered relation. Thus, as is most clearly apparent inFigs. 3 and 6, each segment I1 is provided with a Web member 20extending first inwardly from the segments l1, then axially, and thenoutwardly to connect with a segment I6 in one of the outer rails. Theweb members 20 are formed integrally with'the segments I6 and I1 and, asis apparent from these two figures of the drawing, one segment llis'connected to a segment in one of the outer rails, while the nextsegment I1 is con-- nected to a segment in the other outer rail. Theaxially extending portions of the web members 20 are straight and haveno circumferential offset.

The segments [6 in one outer rail are also connected to two segments inthe opposite outer rail, thus providing the circumferential connectionbetween the segments. For this-purpose, I provide web members 2|. Eachweb .member .21 :is integral with the segments which it connects andextends inwardly from one of the segments Ifijn one outer rail, thenaxially, and then outwardly to another segment I6 in the other outerrail. In the axially extending portion'of each segment-2 I. there is anoffset, indicated .at .22, ior purposes hereinafter described. Theseparations or slits between the segments I6 in each-of theouter railsare out of axial alignment with the separations between the adjacentsegments in the other outer rail, and the separations between thesegments 11 in the intermediate rail are outofaxial-alignment with theseparations between the segments in both of the outer rails. With thisarrangement, when the ring expandsslightly so .thatsuch separations havesome width, oil on the .cylinder wall passing through the separationsin'onerail :will be caught by the segments in the other two .rails.

With the foregoing arrangement of the .web members .20 and .-2 I thereare twice asmany segments in the intermediate rail .as there are ineither of :the .outer :two railssinceeach segment .l'! in theintermediate rail is connected .to only one segment 16111 theouterrailsand there .isone segment H for each of the segments IS. Theforegoing construction of th e.web memberslfland 2! also results in eachouter segment 16 having three web members extending therefrom, -two:ofthem being web membersZI :and the third being a web member v20. The twowebmembers 2:! .are spaced .from-oneanother so that the web memberzlllies therebetween, :and the offsets 22inthe two web members for eachsegmentextend incpposite directions to form enlarged openings, indicatedat 23, in theinner portion of the ring, the openings 23 being .instaggered relation to one another. Between the two web "members .2! :andthe web member 20 are narrow openings .or .slots 24.

The ring may beformed from a strip -;of .sheet .metal punched andsheared in the :manner 1111118- trated in Fig. '7. Such punching ofthe1strip1include punching the slots .24 so that they .extendtransversely of the .strip in pairs and .lieintermediate the outer edgesthereof. From :one-end of each pair of slots 24 the metal is sheared .in

generally rectangular form'to provide the=openings 23. .The metal from:such shearing tor-ms (tongues comprising thesegments I]of-theintermediate rail and is left connected -to theportions of themetal lying between the-slots 24,.suchportions thereby constituting theweb members .20. The metal is also sheared as at 25 along linesextendingfrom the rectangular-shearsto .the outer edges of the strip,.thusforming the segments 16 .and providing the separations or slitsbetween the segments.

The strip .is then bent along longitudinal lines, the segments .IT.formed by the generally rectangular shears being bent, as indicated ,inFig. 6, to extend outwardly intermediate the sides of the ring to formthe intermediate-rail l5. The strip asa whole isalso bent intoagenerally channel-shaped form so that the segments 1 6 formed by theshears 25 form the two outer rails M with the edges .of the strip beingpositionedat-theouter periphery of the ring. The ring is then given itsarcuate form and the necessary grinding on the outer periphery and sidesof the ring is performed. Such bending of the ring results in providinga cross-sectional form which may be said to be generally E-shaped. Eachof the rails comprises a single layer of metal with all three rails,which constitute the horizontal bars of the E,

being of equal radial dimension. The ofiset 20 in the web members 2|provides sufficient circumiierential length for the segments I! toconstitute a complete rail interrupted by separations between thesegments of substantially the same widthlasthe separations or slitsbetween the segments IS. The large openings 23 as well as the .slots :24provide for free fiow of oil inwardly through the ring from both sidesof the intermediate rail l5. Thus, for either direction of .movementduring the reciprocation of the piston,

the oil scraped from the piston wall by the intermediate rail vl.5.as.well as by the outer rails [4 may freely drain back through the ringinto ,thcgroove [2 in the piston, from which it is discharged into thecrankcase by the usual drain .holes provided in the piston.

Iclaim:

l. A piston ring of sheet metal construction comprising a web portionhaving three cylinderengaging rails bent outwardly therefrom and axiallyspaced from one another.

2. A piston ring formed from a single strip of sheet metal foldedlongitudinallyof itself to .form integrally connected portions providingthree-outwardly extending rails adapted to engage thecylinderedgewise,the rails beinglaxiallyspaced.irom one another.

3. A piston ring comprising .a strip .of sheet metal bent to providethree rails axially spaced from one another with each rail having .slitsdividing the rail into a plurality .of cylinder-.engaging segmentsintegrally connected to segments in the other rails, the upper andloweriaceseof eachsegment beingprovided by the two faces of the strip.

4. A piston ring comprising three rails axially spaced from one anotherwith each rail comprising a plurality of cylinder-engaging segments,-andweb members integrally-connecting the segments .in each rail to segmentsin the-otherrails, the web members being spaced from the ends of the sements to .circumferentially separate the :webmembers from each other.

5. A piston ring comprising .a strip -of .shee metal foldedlongitudinally of .itself ,to provide three rails axially spaced fromoneanother :with each rail comprising a plurality of cylinder-engagingsegments, and web members connecting the segments in each rail withsegments ,in the other two rails, the intermediate rail having twice asmany segments as each of theother two rails.

6. .A piston ring comprising three rails axially spaced from one anotherwith each :railcoinprising a plurality of segments, each segment-of theouter two rails having a segment of the intermediate rail connectedthereto with each segment of the intermediate rail connected to .onlyone segment in an-outerrail.

7. A piston ring comprising three rails axial y spaced from one anotherwitheach rail comprising a plurality of segments,-each segmentin eachouter rail having connections to two segments in the opposite outerrail, the segments in the intermediate railhaving connections to thesegments in the outer rails other than the .firstmentioned connections.

8. A piston ring comprising three rails axially spaced from one anotherwith each rail comprising a plurality of segments, each segment in eachouter rail havin two connections respectively to two segments in theopposite outer rail and a third connection to only one segment in theintermediate rail.

9. A piston ring comprising three rails axially spaced from one anotherwith each rail comprising a. plurality of segments, the segments in theintermediate rail being alternately connected to segments in therespective outer rails.

10. A piston ring comprising three rails axially spaced from one anotherand connected solely at their inner peripheries, each rail having aplurality of radial slits dividing the rail into segments, the slits inthe respective rails being circumferentially offset from one another toposition all slits out of axial alignment with each other.

11. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprising a plurality of segments, web membersconnecting the segments of one outer rail with those of the other outerrail, and other web members shorter than the first-mentioned web membersand connecting the segments of the intermediate rail with the segmentsof the two outer rails.

12. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprising a plurality 01 segments, web membersconnecting the segments of the intermediate rail with the segments ofthe other two rails, and other web members connecting the segments ofeach outer rail with those of the other outer rail, said last-mentionedweb members having circumferentially offset portions.

13. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprising a plurality of segments, one set of webmembers connecting the segments of the intermediate rail with thesegments of the two outer rails and including axially extendingportions, and a second set of web members connecting the segments ofeach outer rail with those of the other outer rail and including axiallyextending portions, said portions of the first set of web members beingstraight and said portions of the second set of web members havingcircumferential oifsets.

14. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprisin a plurality of segments, web membersconnecting the segments of the intermediate rail with the segments ofthe other two rails, and a pair of other web members connecting eachsegment of each outer rail with segments of the other outer rail, theWeb members of each of said pairs being circumferentially offset inopposite directions.

15. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprising a plurality of segments, each segment ofeach outer rail having three web members extending therefrom, two ofsaid web members being connected to segments in the other outer rail,and the third web member being connected to a segment in theintermediate rail.

16. A piston ring of sheet metal construction comprising three axiallyspaced rails, each comprising a plurality of segments, each segment ofeach outer rail having two ciroumferentially spaced web membersconnected to segments in the other outer rail and a third web memberpositioned between said two web members and connected to a segment inthe intermediate rail.

17. A piston ring comprising a strip of sheet metal having transverselysheared edges with the strip bent along longitudinal lines and arcuatelyto form a ring having a pair of spaced rails connected by a web portion,the rails comprising a plurality of segments formed by the transverseshears, said strip having intermedite portions sheared and benttherefrom to provide a. segmental rail positioned between and axiallyspaced from said pair of rails.

18. A piston ring comprising a strip of sheet metal bent alonglongitudinal lines and arcuately formed to provide a ring of generallychannel shape cross section having a pair of outwardly extending railswith both edges of the strip at the outer periphery of the ring, saidstrip having portions intermediate its edges sheared and bent therefromto provide a segmental rail positioned between and axially spaced fromsaid pair of rails.

19. A piston ring comprising a strip of sheet metal bent into agenerally channel shape in radial cross section providing a pair ofcylinderengaging rails, the ring having a plurality of tongues punchedfrom the intermediate portion of the strip and bent outwardly betweensaid rails to provide a third cylinder-engaging rail of segmentalconstruction axially spaced from both rails of said pair.

JOHN F. SHIRK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,224,338 Bowers Dec. 10, 19402,259,548 Bowers Oct. 21, 1941 2,267,369 Bowers Dec. 23, 1941 2,325,196Rothweiler July 27, 1943

